Often repeated scans are made during biopsy, draining or vertebroplasty procedures. When a needle is positioned parallel to the X-ray path of an only single projection, serious metal artefacts will occur, which can completely obscure the lesion that is target of the biopsy, draining or vertebroplasty procedure.
Several applications exist, which are used to plan a needle track in a patient, based on a reconstructed volume of that patient. During biopsy taking, for example, several scans are made to verify the progress of the needle towards, for example, a tumour. These applications can make use of computer tomography scan volumes, and in particular of (Xper) CT scan volumes. An (Xper) CT scan consists of a rotational X-ray acquisition. When in one or more X-ray projections the needle is parallel to the path of the X-ray from, for example, an X-ray tube to a detector pixel, very strong metal artefacts occur that are nearly impossible to correct for and that will completely obscure the target lesion.
From JP10211197 A an X-ray CT device is known, wherein the scanning surface of a subject is irradiated with X-ray pulses from an X-ray source, a transmission X-ray amount is detected in an X-ray detector and the conversion output is amplified in a pre-amplifier part, A/D converted and inputted to an image processor. Then, after inputted X-ray transmission data for 360° are converted to the projection data and inverse projection data, the inverse projection data for 360° are added and the tomographic images are reconstituted and displayed at a monitor. At the time the measurement start angle is adjusted so as not to overlap the piercing angle of the piercing needle inserted to the testee body and the measurement start angle of the projected data and an angle 180° opposing the measurement start angle and artefacts generated by the movement during scanning of the piercing needle are suppressed.
Further H. Liu describes ‘metallic needle artefacts in magnetic resonance imaging’ in Journal of Applied Physics 83 (11), 1998, pages 6849-6851. D. Xiao et al, describe ‘software design of transperineal prostate needle biopsy robot’ in the proceeding of the IEEE conference control applications, Canada, 2005, pages 13-18.